<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        function Foo(name){
            this.name = name
            this.age = 20
            // this.test = "你好111"
        }

        //原型对象
        Foo.prototype.fn = function(){
            console.log("f")
        }

        // Foo.prototype.test = "hello"
        Object.prototype.test = "你好222"
        let newFoo = new Foo("张三")
        console.log(newFoo.test)
        let obj = new Object()
        console.log(Object.prototype.__proto__) //null
    </script>
</body>
</html>